
EDM01-02: DAG 4.2S Card User Guide
©2005
28
Version 7: May 2006
Using external
reference
source
To use an external clock reference source, the host PC’s clock must be
accurate to UTC to within one second. This is used to initialise the
DUCK.
The external time reference allows high accuracy time synchronisation.
When the time reference source is connected to the DAG synchronisation
connector, the card automatically synchronises to a valid signal.
dag@endace:~$ dagclock –d dag0
muxin rs422
muxout none
status Synchronised Threshold 596ns Failures 0 Resyncs 0
error Freq 30ppb Phase -15ns Worst Freq 2092838ppb Worst Phase 33473626ns
crystal Actual 100000023Hz Synthesized 67108864Hz
input Total 225 Bad 0 Singles Missed 1 Longest Sequence Missed 1
start Thu Apr 28 14:55:20 2005
host Thu Apr 28 14:59:06 2005
dag Thu Apr 28 14:59:06 2005
Connecting
time
distribution
server
The TDS 2 module connects to any DAG card with a standard RJ-45
Ethernet cable and can be placed some distance from a DAG card.
Existing RJ-45 building cabling infrastructure can be used to cable
synchronisation ports.
The TDS-2 and the DAG synchronisation port should never be connected
to Ethernet or telephone equipment.
CAUTION: Never connect DAG and/or the TDS 2 module to active
Ethernet equipment.
Testing signal
For Linux and FreeBSD, when a synchronisation source is connected the
driver outputs some messages to the console log file
/var/log/messages
.
The
dagpps
tool is used to test a signal is being received correctly and is
of correct polarity. To perform the test, run:
dagpps –d /dag0
.
The tool measures input state many times over several seconds, displaying
polarity and length of input pulse.
Some DAG cards have LED indicators for synchronisation (PPS) signals.
Содержание DAG 4.2S
Страница 1: ......
Страница 5: ...EDM01 02 DAG 4 2S Card User Guide 2005 ii Version 7 May 2006...
Страница 9: ...EDM01 02 DAG 4 2S Card User Guide 2005 4 Version 7 May 2006...
Страница 35: ...EDM01 02 DAG 4 2S Card User Guide 2005 30 Version 7 May 2006...